The present invention relates to a semiconductor device, and is, for example, a technology applicable to a semiconductor device having a current mirror circuit.
One of electric circuits is a current mirror circuit. The current mirror circuit is, for example, used for an amplifier circuit. When the current mirror circuit as the amplifier circuit is provided in a semiconductor device, it is desirable to provide a plurality of output transistors around an input transistor, and to give the same characteristic to these output transistors. For example, a plurality of layout examples of output transistors is described in Japanese Patent Laid-Open No. 1998-256541 (Patent Literature 1).
The present inventor examined reduction in size of a first transistor and a plurality of second transistors in a semiconductor device in which the first transistor serving as an input transistor is sandwiched by the second transistors serving as output transistors. At this time, the present inventor found out that when an abnormal current, such as static electricity, was input to a drain of the second transistor, the abnormal current concentrated on the second transistor closest to the first transistor. When the abnormal current concentrates on the particular second transistor, resistance against the abnormal current of the semiconductor device decreases. A main problem of the present application is to protect the resistance against the abnormal current of the semiconductor device from decreasing. The other problems and the new feature will become clear from the description of the present specification and the accompanying drawings